1. Field of the Invention
The present invention relates to the field of recycling technologies, and more particularly, to a propane bottle recycler that recycles not only the propane containers but also the propane itself.
2. Description of the Related Art
Propane and various blends of propane are generally stored in small steel or aluminum bottles for use in lanterns, camp stoves, camping heaters, and similar propane-burning devices. The propane is stored in the bottle under high pressure in a liquid state. Because propane has a boiling point of −44° Fahrenheit, the propane vaporizes as it exits the bottle. Although there are refillable propane tanks, the typical propane bottle is a DOT 39 cylinder. DOT 39 cylinders are non-refillable, and they must meet certain criteria (for example, ability to withstand pressure) established by the Department of Transportation.
Because propane bottles are often used in connection with camping, national parks are challenged with how to safely dispose of used propane bottles. Traditionally, used propane bottles have been thrown in garbage collection bins along with other garbage, but the propane bottles pose special problems because if punctured, they could explode, and they cannot be composted along with other, compostable garbage. There is one device on the market (the PROSOLV® propane cylinder recycling system made by Justrite Manufacturing) that empties the propane from within the container and then recycles the cylinders as scrap steel, but it is a manual system, it can only be used with one container at a time, and it is not sufficient to address the needs of national parks, which deal with thousands, if not millions, of these bottles per year. In addition, with the PROSOLV® device, the propane is collected in a carbon canister, which absorbs the propane, and then thrown away. The propane itself is not recycled.
There are no issued patents or published patent applications that provide a solution to the problem of recovering the propane inside a closed, non-refillable propane bottle while at the same time crushing the propane bottle so that it can be used as scrap steel—and doing all of this in mass quantities. In the United States alone, 40 million one-pound propane bottles are consumed each year. The steel wasted from throwing away old propane bottles could produce enough recycled steel to build approximately 8000 automobiles annually. Furthermore, the empty steel bottles take up approximately 3.3 million cubic feet of landfill space every year. These problems have not been solved by existing art.
U.S. Pat. No. 5,613,533 (Gold et al., 1997) provides a waste cylinder rupture vessel that is used for releasing and recontaining toxic contents of compressed gas cylinders. The containers are punctured, and the contents of the containers are released into a vacuum chamber. The released gases are then pumped into a second chamber, where they are pumped into new gas cylinders. One of the purposes of this invention is to provide an environmentally acceptable manner of disposing of deteriorated compressed gas cylinders when the contents of the cylinders are unknown.
U.S. Pat. No. 5,441,088 (O'Neill et al., 1995) and U.S. Pat. No. 5,365,982 (O'Neill) disclose a liquid petroleum gas can recycling apparatus that recovers residual gas (such as propane) from used cans. The propane or other liquefied petroleum might be used as a propellant in an aerosol can, or it might be used as a cooking gas. The used cans are placed in a hopper and released one at a time into an inclined feed chute, which leads to a compaction chamber. The compaction chamber is sealed, air is removed from the chamber to avoid explosion, and then the bottom of the can is pierced. The contents of the can exit through the hollow piercing needle into a line for collection and/or recycling, and the can is crushed. This invention was intended to allow for the recycling of propane in countries such as Japan, where reliquefication of residual liquefied petroleum gas (such as propane) is prohibited. Thus, the goal of this invention was to extract the residual cooking gas for recovery and re-use without reliquefying the gas.
U.S. Pat. No. 5,385,177 (O'Neil, 1995) and U.S. Pat. No. 5,322,093 (O'Neil, 1994) both relate to an invention similar to the one described immediately above, except that they include a propellant collection tank for cooling and liquefying the propellant prior to collection.
U.S. Pat. No. 5,067,529 (Gonzalez-Miller et al., 1991) and U.S. Pat. No. 5,174,344 (Gonzalez-Miller et al., 1992) involve another invention directed toward removing the propellant in an aerosol can. This invention is an apparatus that depressurizes, de-caps, and recycles aerosol cans by lowering a vacuum head onto the can top, puncturing the can cap member with a hollow needle, and removing the propellants and other gaseous contents of the can by drawing them through the hollow needle into a storage container.
There are several others patents that deal with crushing and recycling oil filters, processing storage drums, cleaning and crushing cans prior to recycling, and compacting containers of flowable materials (such as food or paint). Examples of such inventions include U.S. Pat. No. 6,772,497 (Rice et al., 2004), U.S. Pat. No. 5,839,350 (Mefferd et al., 1998), U.S. Pat. No. 5,406,691 (Thorne, 1995), U.S. Pat. No. 5,371,911 (Mullinax, 1994), U.S. Pat. No. 5,488,899 (Jennings et al., 1996), U.S. Pat. No. 6,178,882 (Wagner et al., 2001), and U.S. Pat. No. 6,308,618 (Richard et al., 2001). All of these inventions involve the processing of non-pressurized cans or containers that are open to the environment, as opposed to propane cylinders, which are pressurized and closed.